The present invention relates to an improved fastener and more particularly to a strip or aligned row of preformed individual fasteners for conveyor belts, which fasteners are secured in an array or alignment.
Although conveyor belts can be manufactured as continuous or endless belts, this would require manufacture to precise tolerances and possible limits to their adjustment in the application or final assembled product. Therefore, conveyor belts are frequently provided in predetermined lengths, which require belt fasteners to secure the two ends of the belt lengths together to form a continuous belt. The belt fasteners are stapled, riveted or otherwise fastened to the belt ends and thereafter are joined together by a coupling means usually in the form of a hinge pin. The belt fasteners may have various configurations, however, these various configurations aspire to maintain the maximum securing force on the belt end, minimal disruption to the belt configuration, minimal noise, maximum coupling pin size and maximum penetration of the belt end into the gripping or clamping arms without impeding or interfering with the movement of the belt over the sprockets and rollers of the conveyor belt system.
An exemplary illustration of a plurality of fasteners in a prearranged order is shown in U.S. Pat. No. 4,315,349 to Stolz, which ordered arrangement provides a means for visually checking the positioning of the belt end connection, provides stop means to limit the belt end entry into the connector, and secures the various separate elements in their relative position. More specifically, the connector strip, as disclosed and claimed, is comprised of preformed individual elements held together by a wire with a wavy shape, which also operates as a positive stop for the belt end. The thickness of the wavy wire limits the amount of reach-back of the belt end into the space between upper and lower arms of the belt fastener.
U.S. Pat. No. 4,625,369 to Musil provides a belt fastener formed from a blank of metal, which fastener has generally flat upper and lower plates. A strap or hinge loop connects these upper and lower plates and a belt stop extends from one of the plates to limit insertion of a belt end between the plates. The hinge loops from the belt fasteners on the first end of the belt are inserted into the spaces between the belt loops on the hinge fasteners secured to the second belt end and vice versa. The hinge loop penetration is limited by their contact with the facing sides of belt stops located at the inner ends of the spaces between the belt loops. The stop thickness was reduced by flattening, thus decreasing its size. The distance from the plate outer tips to the side of the stop contacting the belt is the reach-back distance. It is always desirable to maximize "reach-back" for a given hinge pin diameter used in the loops of the meshed belt fastener loops. The present invention moves the stop further into the gap between the fastener arms, thus eliminating this belt stop thickness and increasing the amount of reach-back. The belt stops of the fasteners of the present invention do not limit the amount of reach-back of the belt end into the gap between the upper and lower legs of the belt fastener.
As noted above, the amount of belt extension or penetration depth into the gap defined between the hinge loops or individual elements of the belt connectors is defined as "reach-back", and it is desirable to provide as much reach-back in the individual connectors as possible to maximize the amount of belt material between the staples or rivets and the belt end so that longitudinal belt tension forces do not pull the staples or rivets through the belt end. The structures taught and disclosed in the above- noted apparatus limit the penetration depth or reach-back of the belt into the space defined between the upper and lower gripping elements.
Although it appears that increased reach-back for an individual fastener could be provided merely by extending the connecting or fastener arm, it is undesirable to provide too long a fastener arm. The arm acts as a lever when the belt travels around a pulley or sprocket, causing the belt to flex or bend at the ends of the fasteners Continuous flexing and bending causes or may cause the belt to fail in fatigue. Consequently, it is most desirable to utilize as short an arm as physically possible for the size of the belt and the application but to maximize the use, that is reach-back, of the fastener arm.